Discussion Follows New Advance by Sunni Extremists That Threatens City of Erbil

WASHINGTON—The U.S. military is considering launching airstrikes and dropping emergency relief supplies into Iraq to aid members of a religious minority driven into the mountains last weekend by Sunni extremist militants who now are imperiling other areas in northern Iraq, U.S. defense officials said.

The plans were being discussed Thursday at high-level meetings at the White House that also involved the U.S. military leadership, the...